It is already known to provide front bindings for cross-country ski boots which comprise a longitudinally movable locking slide, controlled by an operating lever articulated on the casing of the binding, in a sliding surface fixed to the ski. This slide comprises, at its front end, a hook extending transversely, which is solid with of an inner core extending it towards the back and which extends horizontally above a base plate fixed to the upper face of the ski. This inner core is slidingly engaged in a longitudinal sliding surface which is fixed to the upper face of the ski. Moreover, the binding comprises a frontal abutment extending transversely and located behind the casing of the binding. This abutment extends with respect to the hook of the locking slide with which it cooperates to retain in a locking position, between itself and the hook of the slide, a transversal hooking axle at the front part of the sole of the boot. In unlocked position, the locking slide is so positioned such that the hook of the slide is separated from the frontal abutment. The front of the boot can then be hooked to the binding in engaging the transversal axle solid with the front end of the sole in the space between the hook and the frontal abutment, this engagement occurring from top to bottom in the direction of the upper surface of the ski. To latch the binding, it then suffices to move the operating lever of the binding in such a way as to displace the locking slide and its hook, until it comes into immediate proximity with the frontal abutment. At this point, the hooks tightens the hooking axle of the boot and retains it between itself and the frontal abutment.
Generally, the movable locking slide and the longitudinal sliding surface in which the slide is displaced, are constituted by metal pieces having a high coefficient of friction, and producing, in certain cases, rather significant resistance opposing the movement of the locking slide between locked and unlocked positions. Furthermore, the operation of the binding can also be impeded by the penetration of snow and the formation of ice at the interior of the sliding surface.